Conventional vacuum cleaners generally draw in air and dust from a surface being cleaned by utilizing a suction force generated by a vacuum generator of the vacuum cleaner body. Referring to FIG. 1, a general conventional vacuum cleaner 100 comprises a cleaner body 110 housing a vacuum generator (not shown) therein, an extended flow passage 120 having at least one of an extension pipe 125 and an extension hose 121, connected in fluid communication with the cleaner body 110, and a suction port assembly 130 formed at an end of the extended flow passage 120 to draw in air and the dust from the surface being cleaned.
As seen in FIG. 2, the suction port assembly 130 has a suction head 131 and a suction port 132 extending therein. The suction port assembly 130 is movable along the surface being cleaned during cleaning operation. An articulated portion 135 shaped as a neck connects the suction head 131 in fluid communication to the extended flow passage 120. The extended flow passage 120 is movably connected with the suction head 131 which is lifted up by the articulated portion 135.
A conventional articulated portion 135, as seen in FIG. 1, includes a first connection hole 136 for pivotal connection with the rear side of the suction head 131, and a second connection hole 137 for removable connection with the extension pipe 125 of the extended flow passage 120. The first connection hole 136 is formed in a square shape to guide the air from the suction port 132 towards the extended flow passage 120 even when the articulated portion 135 is pivoted at an angle with respect to the suction head 131.
However, the conventional articulated portion 135 of the suction port assembly 130 only allows pivotal movement between the suction head 131 and the extended flow passage 120 in the lifting direction ‘a’ (FIG. 1) with respect to the surface being cleaned, covering only a limited range of cleaning area. For example, the conventional vacuum cleaner 100 often has difficulty in cleaning crevices or corners of a room.
Additionally, because the first connection hole 136 of the articulated portion 135 is formed in square shape, as shown in FIG. 2, the pivotal movement of the articulated portion 135 is limited to within a predetermined angle θ so that the first connection hole 136 is not exposed to the outside of the suction head 131. If the articulated portion 135 is moved more than the predetermined angle θ, the bottom surface of the suction head 131 is lifted apart from the cleaning surface, thereby reducing cleaning efficiency. Even when the articulated portion 135 is moved within the predetermined angle θ, suction efficiency is often reduced due to the partial blocking of the first connection hole 136 by inner structures of the suction head 131.